it's true, but I don't think I'd suggest it for just anyone wanting a regular computer.
I have a Pi, it works fantastically for things such as 1080p video to your TV, a teamspeak server, a radio server, anything you can think of really. Windows is not necessary for a lot of these mundane tasks. however my OS has been corrupted about a million times now and I have no idea why. I guess NEVER take the SD card out.
Using raspberry pi as a desktop computer is okay. Office suits, browsing the net and even watching youtube videos and other video streaming website, programming and even electronic projects. The pi is a cheap but amazing device than can be everybody's favorite.
The newest Raspberry Pi 3 is definitely a fantastic lightweight low cost home server however their are limitations to what you can do but that 1gb ram is enough to run a fully functional webserver, though it would be slow under load. I have set mine up so that i can turn my bedroom light on/off from anywhere in the world. Something more useful though would be hooking up an external drive and running a home media server. Although you could use one as a basic homework PC you wouldn't want it as a full time computer although the high clock speeds and quad core processors sound amazing they like so many of the CPU functions your home PC will have.
You will likely struggle to watch a youtube video, It might however be better than 80% of the cheap android tablets out their if you make your own.
I think Rasberry pi is a future technology. If we can add memory, change the processor and other things, it will be very interresting for the hackers and for the future !